Datasheet LT3790 (Analog Devices) - 10

LT3790
PIN FUNCTIONS BST2 (Pin 22):
Bootstrapped Driver Supply. The BST2 pin lows the inductor current to flow negative. When the pin swings from a diode voltage below INTVCC up to a diode voltage is less than 0.3V, the part runs in discontinuous voltage below VOUT + INTVCC. conduction mode and does not allow the inductor current to flow backward. This pin is only meant to block inductor
NC (Pin 23):
No Connect Pin. Leave this pin floating. reverse current, and should only be pulled low when the
TG2 (Pin 24):
Top Gate Drive. Drives the top N-channel output current is low. This pin must be either connected to MOSFET with a voltage equal to INTVCC superimposed on INTVCC (pin 13) for continuous conduction mode across the switch node voltage SW2. all loads, or it must be connected to the C/10 (pin 4) with
ISP (Pin 25):
Connection Point for the Positive Terminal a pull-up resistor to INTVCC for continuous conduction of the Output Current Feedback Resistor. mode at heavy load and for discontinuous conduction mode at light load.
ISN (Pin 26):
Connection Point for the Negative Terminal of the Output Current Feedback Resistor.
CLKOUT (Pin 33):
Clock Output Pin. A 180° out-of-phase clock is provided at the oscillator frequency to allow for par-
SNSP (Pin 27):
The Positive Input to the Current Sense alleling two devices for extending output power capability. Comparator. The VC pin voltage and controlled offsets between the SNSP and SNSN pins, in conjunction with a
SYNC (Pin 34):
External Synchronization Input Pin. This resistor, set the current trip threshold. pin is internally terminated to GND with a 90k resistor. The internal buck clock is synchronized to the rising edge
SNSN (Pin 28):
The Negative Input to the Current Sense of the SYNC signal while the internal boost clock is 180° Comparator. phase shifted.
TEST1 (Pin 29):
This pin is used for testing purposes only
RT (Pin 35):
Frequency Set Pin. Place a resistor to GND and must be connected to SGND for the part to operate to set the internal frequency. The range of oscillation is properly. 200kHz to 700kHz.
SGND (Pin 30, Exposed Pad Pin 39):
Signal Ground.
VC (Pin 36):
Current Control Threshold and Error Amplifier All small-signal components and compensation should Compensation Point. The current comparator threshold connect to this ground, which should be connected to increases with this control voltage. The voltage ranges PGND at a single point. Solder the exposed pad directly from 0.7V to 1.9V. to the ground plane.
FB (Pin 37):
Voltage Loop Feedback Pin. FB is intended for
PWMOUT (Pin 31):
Buffered Version of PWM Signal for constant-voltage regulation. The internal transconductance Driving Output Load Disconnect N-Channel MOSFET. The amplifier with output VC will regulate FB to 1.2V (typical) PWMOUT pin is driven from INTVCC. Use of a MOSFET through the DC/DC converter. with a gate cutoff voltage higher than 1V is recommended.
OVLO (Pin 38):
Overvoltage Input Pin. This pin is used for
CCM (Pin 32):
Continuous Conduction Mode Pin. When OVLO, if OVLO > 3V then SS is pulled low, the part stops the pin voltage is higher than 1.5V, the part runs in fixed switching and resets. Do not leave this pin open. frequency forced continuous conduction mode and al- 3790fa 10 For more information www.linear.com/LT3790 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Electrical Characteristics Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts